238 The isotope of plutonium Pu is used to make thermoelectric power sources for spacecraft. Suppose that a space probe was 238 launched in 2012 with 4.0 kg of Pu. Part 1 of 2 ki 238 (a) If the half-life of Pu is 87.7 yr, write a function of the form Q (t) = 20e 238 to model the quantity Qt) of Pu left after t years. Round the value of k to five decimal places. Do not round intermediate calculations. 0.00791 Q(t)= 4.0e Part: 1 / 2 Part 2 of 2 238 (b) If 1.4 kg of Pu is required to power the spacecraft's data transmitter, for how long after launch would scientists be able to receive data? Round to the nearest year. Do not round intermediate calculations. Scientists will be able to receive data for approximately yr